The U.S. military in Afghanistan says catching accused terrorist Osama bin Laden offers different challenges than did the capture of former Iraqi leader Saddam Hussein.

Forces with the U.S.-led coalition continue to search for Osama bin Laden, the head of the al-Qaida terror network, as well as for Mullah Omar, who led Afghanistan's hard-line Taleban regime, ousted two years ago.

With the capture Saturday of another fugitive leader, Iraq's Saddam Hussein, Afghan news media have been asking whether coalition troops are any closer to finding Osama bin Laden and Mullah Omar.

Lieutenant Colonel Bryan Hilferty, a U.S. military spokesman, says the search for the two men is taking longer than the hunt for Saddam Hussein, because they work in small, tightly knit networks.

"They have smaller organizations," said Bryan Hilferty. "He [Saddam Hussein] was the head of a large organization so there were probably more people to rat on him."

He adds that as in the case of Saddam Hussein, good human intelligence will be the only way to find the two wanted men, both of whom were last seen in Afghanistan.

But Lieutenant Colonel Hilferty says coalition efforts in Afghanistan are much more than conducting manhunts.

He points out that there have been no attacks on the Afghan constitutional assembly, despite threats by anti-government insurgents to disrupt the gathering.

"I think we have stopped hundreds of attacks," he said. "But how do you prove something that has not happened? How does a policeman who is walking the streets of Kabul prove that a crime was not committed because he was there?"

The U.S. military has more than 10,000 troops in Afghanistan, as part of a multi-national coalition of about 12,000.